Delayed disease progression for patients with a treatment-resistant form of prostate cancer.

April 29, 2020
| By Will Doss

For the first time,advancedprostate cancer has been treated based on the genomic makeup of the cancer, delaying progression for patients with metastatic castration-resistant prostate cancer, a deadly and treatment-resistant form of the disease.

Published April 28 in theNew England Journal of Medicine, the clinical trial represents a breakthrough in treating this cancer and for precision medicine more broadly, according toNorthwestern Medicine oncologistDr. Maha Hussain,the Genevieve E.TeutonProfessor of Medicineandco-lead authorof the study.

In 2020, therewill be an estimated191,930new cases of prostate cancer in the United States, with more than33,000deaths from the disease,accordingto the NationalCancer Institute.

In particular, metastaticcastration-resistant prostate cancer,in which the cancer has spread beyond the prostate and grows despitehormonetreatments, continues to be deadlydespiteadvances in treatment, according to Hussain.

This lethality ispartly dueto gene mutations in BRCA1,BRCA2and other similar genes thathelp cells maintain stability of genetic material.Normally, these genes help repair DNA damage, but whenthey aremutated cells are not repaired correctly.

These mutations complicatethe biology of the cancer, but can also be exploited by drugs such as olaparib — a drug that blocks cell repair proteins and has been used in ovarian and breast cancers with similar repair mutations.

The current trial enrolled patients with one or more of these mutations who were randomized to receive either standard hormone therapy orolaparib.Patients in the olaparib cohort experienced delayed disease progressionan average of seven months compared to three months for the standardtreatmentcohort.

About 60 percent of men in the olaparib groupshowed no disease progressionat six months, compared to 23 percent in the standard cohort. The benefit was observed across the board, irrespective of the patient’s prior treatment, where the cancer had spreadto(bone, liver or lymph nodes), the patient’s PSA (prostate-specific antigen) or age.

The drug is currently under review by the Food and Drug Administration.

“The approach in the treatment of this disease to date has been a ‘one size fits all approach,’yet different patients respond differently to the current standard of care treatments,” Hussain said. “Better personalization of therapy allows for maximizingthebenefittoriskratio.”

This study was sponsored by AstraZeneca and is part of an alliance between AstraZeneca and Merck Sharp & Dohme, a subsidiary of Merck.